1. Field of the Invention
The invention relates to a system and a method for converting an aircraft from a flight condition lying outside a permissible flight condition range to a flight condition lying with the permissible flight condition range.
2. Discussion of Background Information
With conventional aircraft, reliable maneuvering in the range outside the flight range limits is solely the responsibility of the pilot. Depending on the type of aircraft and frequency of deployment, different aircraft loss rates are known because limits are exceeded (e.g., due to speed being too low).
With most fixed-wing and variable-wing aircraft, the forces for stabilizing and controlling flight attitude and flight path are generated by air flow on movable control surfaces, such as elevators, the rudder and ailerons. If, in addition, the inherent dynamics of aircraft are unstable, control forces are required to stabilize the aircraft movement in every flight attitude. If the airspeed falls below a technically preset minimum typical for the aircraft, the forces forming on the control surfaces of the aircraft will become too small to maintain control of the aircraft position and the flight path in a stable manner. The risk of an aircraft crash arises, e.g., through a tailspin, from which the pilot cannot, in many cases, pull up.
To support the pilot, systems are known that produce an acoustic signal to alert the pilot to the impending danger of exceeding a flight range limit (e.g., by reaching a minimum speed). The pilot must then start a pull-up maneuver immediately and perform it manually.
From the document WO 00/77586 A2, an autopilot control device is known for controlling the movement of an aircraft in a fluid medium in any one of a pre-stall region, a stall region, and a post-stall region. Control devices are provided that convert the aircraft from a flight condition lying outside a permissible flight condition range to a flight condition lying within the permissible flight condition range.
Furthermore, auto pilot systems are generally known which can be switched on by the pilot in order to take over certain control or regulating functions, e.g., the altitudes or speed control.